Origin of the enigmatic, circular, barren patches ('Fairy Rings') of the pro-Namib

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dc.contributor.authorAlbrecht, C. F.en_ZA
dc.contributor.authorJoubert, J. J.en_ZA
dc.contributor.authorDe Rycke, P. H.en_ZA
dc.date.accessioned2011-05-15T15:55:19Z
dc.date.available2011-05-15T15:55:19Z
dc.date.issued2001
dc.descriptionCITATION: Albrecht, C. F., Joubert, J. J. & De Rycke, P. H. 2001. Origin of the enigmatic, circular, barren patches ('Fairy Rings') of the pro-Namib. South African Journal of Science, 97(1):23-27.
dc.descriptionThe original publication is available at https://journals.co.za
dc.description.abstractWe have studied the enigmatic, circular, barren patches on the edge of the pro-Namib Desert in Namibia. An aerial photograph of the Wolwedans area (25°4.5′S, 15°59.5′E) showed that the patches had an average diameter of 6.1 m and an ordered distribution with an R-value of 1.68, suggesting a termite-associated origin. We postulate that there is an active evolutionary process of circular patch formation, involving genesis, growth, maturation and extinction. Stipagrostis uniplumis seedlings growing in the moist inner soil of barren patches, after rains, appeared to lack root side-hairs when compared to similar plants growing outside the patch and these seedlings invariably died when the rains subsided. Growth experiments with Cynodon dactylon in inner and outer soil samples showed that these grass seedlings could survive cycles of dehydration and hydration only when growing in outer soil. Seedlings in the inner soil collapsed and died under similar conditions. This suggested that there is a biological factor in the inner soil, which inhibits resistance to dehydration, possibly through inhibition of side-root growth and/or maintenance. We postulate that termites are linked to this biological factor in some unknown manner and that the barren patches have an evolutionary advantage for the termites by acting as water traps. Direct experiments showed five-fold more water in soil samples from the barren patches than between them. Preliminary attempts to indicate or isolate the putative abiosis factor with HPLC were not successful and more sophisticated analytical techniques are called for.
dc.description.urihttps://journals.co.za/content/sajsci/97/1-2/EJC97280
dc.description.versionPublisher's version
dc.format.extent5 pages
dc.identifier.citationAlbrecht, C. F., Joubert, J. J. & De Rycke, P. H. 2001. Origin of the enigmatic, circular, barren patches ('Fairy Rings') of the pro-Namib. South African Journal of Science, 97(1):23-27
dc.identifier.issn1996-7489 (online)
dc.identifier.issn0038-2353 (print)
dc.identifier.urihttp://hdl.handle.net/10019.1/9707
dc.language.isoen_ZAen_ZA
dc.publisherAcademy of Science of South Africa
dc.rights.holderAuthors retain copyright
dc.subjectNamibRand Nature Reserve
dc.subjectPlants
dc.subjectSeedlings
dc.titleOrigin of the enigmatic, circular, barren patches ('Fairy Rings') of the pro-Namiben_ZA
dc.typeArticle
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